A pressure sensor employing MEMS (Micro Electro Mechanical Systems) technology includes, for example, a piezoresistance change type and an electrostatic capacitance type. On the other hand, a pressure sensor employing spitronics technology has been proposed. In the pressure sensor employing spitronics technology, a resistance change corresponding to a strain is detected. In the pressure sensor employing spitronics technology, a pressure sensor of high sensitivity is desired.